Explain the reasoning behind the Supreme Court's rulings in regard to industry. How was the court defining freedom?

I assume that you are asking about cases that came before the Supreme Court in the early 1900s. This was a time when the government of the US (and state governments) was making some efforts to regulate industry. The Supreme Court’s rulings in these cases generally disallowed such regulations. In doing so, the Court defined freedom in a very broad way, one which worked to the benefit of employers rather than employees.

In the Supreme Court cases that I think your question refers to, the Court used a doctrine that is now referred to (but was not at the time) as “substantive due process.” The 5th and 14th Amendments to the Constitution say that the federal and state governments cannot deprive anyone “of life, liberty, or property, without due process of law.” In today’s jurisprudence, this is interpreted to mean that you a person cannot be fined, jailed, or executed without having been put on trial.

The doctrine of substantive due process extended the concept of liberty. Liberty no longer referred simply to freedom from being put in jail. Instead, it also referred to economic liberty. The Court began to rule that governments could not pass laws that infringed on people’s economic liberty. This idea of economic liberty was defined very broadly.

This started with the case of Allgeyer v. Louisiana, ruled on in 1897. In that case, the State of Louisiana passed a law saying that people in that state could not make contracts with marine insurance companies outside the state. The Court ruled that this took away people’s liberty to make contracts with whoever they wanted. Thus, the law was unconstitutional because it infringed on people’s economic liberty.

The most famous case using this line of reasoning was Lochner v. New York, which was heard in 1905. In that case, the state of New York had passed a law saying that bakers could not work more than 10 hours a day and 60 hours a week. The idea was to protect the bakers from being forced to work excessive hours. However, the Supreme Court ruled that this law actually took away the bakers’ liberty. It said that bakers (and everyone else) should have the liberty to make contracts in which they promise to work as many hours as they wished. The government, it said, could not take away that liberty by making laws such as the one that New York had made. During the time that is called the “Lochner Era” the Court made many more rulings like this, such as one in which it declared that a minimum wage law was an unlawful infringement on the liberty of contract.

During this time, then, the Court was defining freedom in a way that seems strange to us today. It was saying that economic freedom was a fundamental freedom. More strangely, it was saying that any law that set up rules about working conditions could be seen as a violation of freedom/liberty. Freedom was defined in a way that said that workers had to be free to work long hours for very low pay.